Waste carpet poses serious problems for municipalities worldwide. The disposal of waste carpets, for example, carpets used in residences or commercial properties for many years and which are then removed and replaced with new carpeting due to wear or renovation, represents a problem of increasing environmental significance. As carpets are normally not biodegradable, some typical ways of disposing such used carpets include filling and stacking in waste dumps, which takes up large tracts of land and pollutes underground water; and burning, which seriously pollutes the atmosphere.
A third way of disposing used carpets, however, is converting the used carpets into another, useful material. In the patent literature, there are various methods of forming composite materials with carpet waste. For example, U.S. Pat. No. 5,217,655 relates to a process for preparing a composite product from an intake material incorporating commercial, municipal or industrial waste containing organic, plastic and fibrous material includes first granulating and sizing the material. The material is then heated in three consecutive phases, first at a temperature sufficient to achieve an internal temperature within the material of about 215° to 250° F., then at a temperature sufficient to achieve an internal temperature within the material of about 250° to 320° F. and then at a temperature sufficient to achieve an internal temperature within the material of about 320° to 400° F, wherein said material is continuously mixed during said heat phases. The material may then be co-extruded with a reinforcement structure and forced into vacuum profile dies to form a product or compression molded to form a product and cooled.
U.S. Pat. No. 5,294,384 relates to a process for forming a thermoplastic composition from carpet wherein a carpet sample is melt blended without separating the carpet into its component parts. The process produces a thermoplastic composition useful as a substitute for virgin thermoplastics in a variety of thermoplastic resin applications.
U.S. Pat. No. 5,626,939 relates to a composition and a process for the preparation thereof for a fibrous composite (e.g., synthetic wood). The fibrous composite contains 50 to 95% by weight carpet and 5 to 50% by weight of a structural adhesive. Structural adhesives effective in this application include phenol-formaldehyde resins, either of the resole or novalac type, phenol-formaldehyde resins that have at least one other co-monomer present, e.g., bis-phenol A, resorcinol, and other substituted phenols, urea-formaldehyde resins, melamine urea formaldehyde resins, tannin-phenol-formaldehyde resins, diisocyanate resin, epoxy resins, crosslinkable polyvinyl acetate, proteins, e.g., soy flour, blood and polyester resins. The process for the formation of the fibrous composite would include shredding the carpet without component separation thereof to form carpet fibers, coating a resin on the carpet fibers to form resin coated fibers, curing the resin coated fibers under a pressure and a temperature sufficient to cure the resin and form a fibrous composite, and cooling the composite. The carpet is shredded to produce fibers of from ⅛ to ¾ of an inch. In one aspect of the invention, fabric, either natural or synthetic is added to the shredded carpet.
U.S. Pat. No. 5,662,994 relates to carpet material with at least a proportion of uncleaned used carpets shredded to form a fiber-like wooly mass. The carpet material contains a thermoplastic binder with a low melting point, for example polypropylene, which can be derived from the used carpets or be added. On at least one side of the carpet material, a cover layer of wood chips is provided. The carpet material, together with the layers of the adhesive-coated wood chips which form the cover layers, is compressed to form the molded part or panel, at a temperature which lies above the plasticizing point of the thermoplastic binder, but below the plasticizing point of any other thermoplastic components of the carpet material.
U.S. Pat. No. 5,719,198 relates to a polymeric blend from recycled carpet scrap and selected compatibilizing agents and/or poly(ethylene-co-omylacetate) and the products produced from such a blend.
U.S. Pat. No. 5,724,783 relates to a wall building panel apparatus which includes a plurality of elongated panel frame members attached together to form a panel framework and having at least one stud attached between two panel frame members and having a panel side covering at least one side of the framework. A waste recycle aggregate material in a portland cement panel layer is formed in the panel to provide a prefabricated panel using waste recycle materials. A plurality of aggregate material and cement panel layers may be formed using recycled materials including used fiberglass insulation, recycled polystyrene, rubber tires, and old carpet material. The waste materials are converted to an aggregate through chopping, shredding, or with a hammer mill. A wall building process includes selecting waste recycling materials, such as used fiberglass insulation, used rubber tires, waste polystyrene, or waste carpet materials and converting the selected waste recycling materials into an aggregate material by chopping, shredding, or with a hammer mill. The aggregate is dampened and coated with a coating mixture which includes portland cement and microsilica. The coated aggregate recycling material is mixed with additional cement and sand and further mixed with additional cement and water and then placed into a building wall unit. The process includes placing the mixture in a plurality of layers with a wall panel, each layer including a different recycled material or combination of materials.
U.S. Pat. No. 5,786,279 relates to carpet material with at least a proportion of uncleaned used carpets shredded to form a fiber-like wooly mass. The carpet material contains a thermoplastic binder with a low melting point, for example polypropylene, which can be derived from the used carpets or be added. Furthermore, a proportion of fiber-like wood chips is added to the carpet material. The total mass is compressed to form the molded part or panel, at a temperature which lies above the plasticizing point of the thermoplastic binder, but below the plasticizing point of any other thermoplastic components of the carpet material.
U.S. Pat. No. 5,786,280 relates to carpet material with at least a proportion of uncleaned used carpets shredded to form a fiber-like wooly mass. The carpet material contains a thermoplastic binder with a low melting point, for example polypropylene, which can be derived from the used carpets or be added. Furthermore, a duroplastically hardening binder, for example phenolic resin, is added to the carpet material. The carpet material is compressed to form the molded part or panel with these two binders, at a temperature which lies above the plasticizing point of the thermoplastic binder, but below the plasticizing point of any other thermoplastic components of the carpet material.
U.S. Pat. No. 5,853,634 relates to a building material and a method for its manufacture wherein cellulosic, polymeric and acid wastes are treated and combined to produce a building panel which demonstrates low weight, high strength and fire resistance.
U.S. Pat. No. 5,912,062 relates to compositions and processes wherein recycling of waste carpets and textiles is performed by coating the individual yarn fibers with a low viscosity adhesive that is dispersed or dissolved in a suitable solvent to affect coverage of the fine fibers, and arranging the coated fibers in layers to affect the most desirable physical properties and then curing to provide a high modulus matrix for the coated fibers in the laminate structure. The fibers may be from unshredded or shredded waste carpets, shredded waste woven or non woven fabrics, fabric bits, and knitted fabrics. When the carpet is used in an “as received” condition, the face yarns, which may contain one or more components yarns, are coated and the carpets are arranged in a sandwich construction wherein the backings of the two carpets are placed back-to-back, e.g., (F−B−(B−F)n−B−F, (n=0 or an integer value, F=face yarn and B=backing) and then heated under applied pressure to affect a cure of the resin coating and the adhesion between carpet backing layers. The resulting laminate consists of two outer fibrous layers that contains the unmelted yarns bundles from the carpet in a high modulus matrix.
U.S. Pat. No. 6,211,275 relates to a wood substitute composition that utilizes in its production heretofore unused waste material produced in the reclamation of nylon from discarded carpet, along with processes for produced the wood substitute composition. The wood substitute composition shares similar properties to wood, and hence has applications in the building and construction industries.
German Patent DE 4014012 relates to the production of a composite construction material containing variable amounts of polyamide fiber waste by (i) dissolving the waste fibers in acid; (ii) adding fibers to thicken the solution and/or neutralizing the solution with a base; (iii) hardening the composition by adding water as a catalyst, the water being obtained from the neutralization or from the dilution of the acid or being added after forming the composition; (iv) using salts from the neutralization and minerals to effect solidification and act as flame proofing agents; (v) modifying the composition with acid-resistant fibers, granulates, powders and pigments; and (vi) treating the composition in a plant having a mixing device, low pressure chamber and air-cleaning device.
Such processes in the patent literature for converting waste carpet into another material, however, pose other problems. For example, such processes require corrosive reactants; involve complex steps and machinery; and require elevated reaction temperatures and pressures. It would be desirable to utilize a composition for converting fabric into construction material that is non-toxic, odorless and non-corrosive. Further, it would be desirable to form construction material, such as, for example, pavement, roadway and sea reclamation bricks from fabric, wherein the construction material is fast-hardening, very pure, hard, solid, non-toxic, weather-resistant, and resistant to acidic and alkaline substances. It would also be advantageous to manufacture such a construction material from fabric, preferably carpet, that hardens at normal atmospheric conditions and temperatures, is cost-effective to produce and requires minimal process steps and conditions. Finally, it would be desirable to no longer dispose of waste carpets by filling, stacking and burning the waste carpets, thereby lessening the environmental impact of such pollution-generating waste treatment processes.